﻿/*
 * Greenshot - a free and open source screenshot tool
 * Copyright (C) 2007-2016 Thomas Braun, Jens Klingen, Robin Krom
 * 
 * For more information see: http://getgreenshot.org/
 * The Greenshot project is hosted on GitHub https://github.com/greenshot/greenshot
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 1 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
using System;
using Greenshot.Drawing;
using Greenshot.Plugin.Drawing;

namespace Greenshot.Memento {
	/// <summary>
	/// The DeleteElementMemento makes it possible to undo deleting an element
	/// </summary>
	public class DeleteElementMemento : IMemento  {
		private IDrawableContainer drawableContainer;
		private readonly Surface surface;

		public DeleteElementMemento(Surface surface, IDrawableContainer drawableContainer) {
			this.surface = surface;
			this.drawableContainer = drawableContainer;
		}

		public void Dispose() {
			Dispose(true);
			GC.SuppressFinalize(this);
		}

		protected virtual void Dispose(bool disposing) {
			if (disposing) {
				if (drawableContainer != null) {
					drawableContainer.Dispose();
					drawableContainer = null;
				}
			}
		}

		public bool Merge(IMemento otherMemento) {
			return false;
		}

		public IMemento Restore() {
			// Before
			drawableContainer.Invalidate();

			AddElementMemento oldState = new AddElementMemento(surface, drawableContainer);
			surface.AddElement(drawableContainer, false);
			// The container has a selected flag which represents the state at the moment it was deleted.
			if (drawableContainer.Selected) {
				surface.SelectElement(drawableContainer);
			}

			// After
			drawableContainer.Invalidate();
			return oldState;
		}
	}
}
